From the Guidelines
The initial diagnostic approach for a patient presenting with mediastinal and hilar lymphadenopathy should begin with a thorough history and physical examination, followed by chest imaging, and if necessary, tissue sampling through minimally invasive procedures such as endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) as recommended by the European Society of Gastrointestinal Endoscopy (ESGE) in cooperation with the European Respiratory Society (ERS) and the European Society for Thoracic Surgery (ESTS) 1.
Initial Evaluation
The diagnostic workup should start with a detailed history and physical examination to identify any symptoms or signs that may suggest an underlying condition. Chest imaging, preferably a high-resolution CT scan of the chest with contrast, is essential for evaluating the size, location, and characteristics of the lymph nodes. This information is crucial for guiding further diagnostic steps.
Laboratory Tests
Laboratory tests should include:
- Complete blood count
- Comprehensive metabolic panel
- Inflammatory markers (ESR, CRP)
- Specific tests based on clinical suspicion, such as:
- ACE levels for sarcoidosis
- Tuberculin skin test or interferon-gamma release assay for tuberculosis
- Serologic tests for fungal infections or HIV
Tissue Sampling
If the diagnosis remains unclear after non-invasive testing, tissue sampling is necessary. EBUS-TBNA is recommended for patients with suspected sarcoidosis with mediastinal and/or hilar adenopathy, as well as for those with suspected tuberculosis who require lymph node sampling 1. More invasive procedures like mediastinoscopy or video-assisted thoracoscopic surgery may be required if EBUS is non-diagnostic.
Pathologic Examination
The tissue obtained should undergo pathologic examination, including:
- Histology
- Cytology
- Flow cytometry if lymphoma is suspected
- Microbiological studies, including cultures for bacteria, fungi, and mycobacteria
This systematic approach allows for accurate diagnosis of the various conditions that can cause mediastinal and hilar lymphadenopathy, including malignancies, infections, and granulomatous diseases, as outlined in guidelines for lung cancer diagnosis and management 1.
From the Research
Initial Diagnostic Approach
The initial diagnostic approach for a patient presenting with mediastinal and hilar lymphadenopathy involves a combination of clinical, radiological, and pathology findings 2. The following steps can be taken:
- Obtain a thorough medical history and perform a physical examination to identify any underlying conditions or symptoms that may be related to the lymphadenopathy.
- Use thoracic imaging modalities such as chest radiography (CXR) and computed tomography (CT) to assess the size, shape, borders, density, and enhancement patterns of the lymph nodes 3.
- Consider the use of endosonographic modalities such as endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for tissue diagnosis, as they have emerged as a cornerstone in the diagnosis of mediastinal lymphadenopathy 2, 4.
Differential Diagnosis
The differential diagnosis for mediastinal and hilar lymphadenopathy is broad and includes:
- Malignant conditions such as lung cancer, lymphoma, and metastases 2, 5, 3.
- Granulomatous conditions such as sarcoidosis and tuberculosis 2, 5, 3.
- Inflammatory conditions such as amyloidosis 4.
- Immune-related adverse events (irAEs) such as sarcoidosis-like reactions induced by immune checkpoint inhibitors like pembrolizumab 6.
- Occupational diseases such as chronic beryllium disease and histoplasmosis 5.
Diagnostic Challenges
The diagnosis of mediastinal and hilar lymphadenopathy can be challenging due to the broad range of potential causes and the need to distinguish between malignant and benign conditions 5, 3. A systematic imaging approach and the use of tissue diagnosis modalities can help enhance diagnostic accuracy and guide appropriate clinical management 3. Additionally, the involvement of extra-mediastinal nodes can provide diagnostic clues to systemic diseases 3.